Surgical guidance system for locating a detectable marker within a subject; medical apparatus and instruments with embedded hardware and operating system software for use in surgical guidance procedure; medical devices, apparatuses, and instruments with embedded hardware and software for determining and communicating the location of detectable marker within a patient; medical device, namely, marker used as a location indicator; medical device, namely, an implantable marker used as a location indicator; medical device, namely, a location indicator capable of being attached to surgical tools; medical device, namely, a location indicator having adhesive component for attachment to surgical tools; medical device, namely an electric field generator; medical device, namely, a pad for positioning under a surgical patient for surgical guidance in 3D volume